Process of treating tungsten ores.



entrain era-res Parana orator.

FEEDERIGK an. enema, or NIAGARA rants, NEW YORK, ASSIGNOR 'ro ELEo'rno I mn'ramuneroar. comramr, or new YORK, n.

reloca es or meantime rnnes'rnn cans. Y

"52., A conrona'rron or west VIRMFTIA.

Lqlgitfliiifi Specification of Letters Patent.

No Drawing.

Patented Dec. 116, 1913..

Application filed- October 22, 1912. Serial No. 727,215.

tion.

This invention relates to the treatment of such tungsten ores as contain material proportions of phosphorus, the object of the invention being, the provision of methods whereby the phosphorus-content of such ores may be so far reduced as to render the ores directly available for such purposes as the L preparation of metals or alloys low in phosphorus. The term ores is herein employed to include concentrates.

I have found that certain ores of tungsten, including ferberite from Boulder county, Colorado, contain very considerable proportions of phosphorus, which in special cases may attain 0.6 to 0.7 per cent. Such ores consist largely of iron tungstate with a gangue of silicious character, the phosphorus bein usually associated both with the mineral and the gangue in extremely variable proportions. Ores presenting similar conditions are wolframite, an iron tungstate containing considerable manganese, and hiibnerite, an iron-manganese tungstate 1n which manganese largely predominates. Such ords are herein referred to as ores of the iron-tungstate type. I have discovered that it is possible to remove a material proportion, and in some cases all, or nearly all, of the phosphorus from these ores by a treatment involving the solution of the phosphorus in acid reagents, without substantial solution or loss of tungsten. In other words, the eifect of an acid treatment under proper conditionsis to in: crease the-ratio of tungsten to phosphorus,

expressed as 1 2, converting high-phosphorus tions of 200 cubic centimeters of acid per kilogram of ore. The solution proceeds at ordinary room temperatures, dissolving from 30 to 90 per cent. of the phosphorus in the course of a few hours wlthout substantial loss of tungsten, the loss of tungsten under these conditions being usually less than one per cent. At somewhat higher temperatures, say -100 (l, the solution of phosphorus is-more rapid but the loss of tungsten is materially greater. At the same time, very considerable quantities of iron are dissolved,

thus effecting a concentration of the tungsten-content of the ore. Following the acidtreatment, the ore is thoroughly washed with water to remove the dissolved substances. This simple acid treatment is effective for certain ores, usually those which contain relatively small percentages of phosphorus, or

in which the ratio glis relatively high, say

250 or more. It is therefore frequently possible, by means of this acid-treatment, so to reduce the phosphorus-content of a given ore as to render it available for the direct preparation of low-phosphorus ferrotungsten. There are however many ores which do not respond to a sufiicient degree to the being most easily and economically accomplished. For example, the ore is crushed to 1042 mesh and subjected to an oxidizing roast, with stirring, at a red heat or some what lower. The acid-treatment may be applied to the roasted ores without further crushing. The efiiciency of the process may however be further increased in certain cases by a finer subdivision of the ores, either before or after the roasting.

The conditions of the acid treatment as applied to the roasted ores may be substantially as above described with reference to. the raw ores. Such treatment of roasted ores has been found effective to remove up 'to' 90 per cent. or even more of the contained phosphorus, without material loss of tung- Roasting followed Sample. Raw ore. Acid treatment only. by acid treatment Ratiog Ratio The invention is not restricted to the use of concentrated sulfuric acid as a solvent, as results of a similar character may be obtained With other acids or acid-reacting reagents, as diluted sulfuric-acid, hydrochloric acid or the like. Mixed reagents may also be used, good results having been obtained with sulfuric acid containing a small pro portion of nitric acid, potassium chlorate, and other oxidizing agents. Ghlorin and chlorin-yielding mixtures have not proven effective for the purposes'of this invention. In the use of these acid baths it may be desirable to dispose the ore in proximity to an A insoluble anode connected in a direct electric circuit, for example in proximity to an anode of lead in the case of sulfuric acid, whereby the solvent effect of the acid 1s somewhat accentuated.

Preferably the purified ores are smelted in presence of a metallic reducing agent,

rosrsee usually silicon, the reduction being accomplished in an electric furnace, in accordance with the methods disclosed in my prior patents. By this procedure it is possible to obtain a ferrotungsten which is low, both in acid reagent, under conditions to increase the ratio of tungsten to phosphorus.

I 2. The process of purifying ores of the iron-tungstate type, which consists in heating the ores, and then subjecting the same to-the action of a suitable acid reagent, under conditions to increase the ratio of tungsten to phosphorus.

3. The process -of purifying ores of the iron-tungstate type, which consists in sub- -jecting the same to the action of sulfuric acid under conditions to increase the ratio of tungsten to phosphorus.

4. The process of purifying ores of the iron-tungstate type, which consists in heating the ores and then subjecting the same to the actionv of sulfuric acid under conditions to increase the ratio of tungsten to phosphorus.

In testimony whereof I aflix my signature in presence of two witnesses.

FREDERICK M. BEOKET. Witnesses:

J. N. DEINHARDT, D. BURGESS. 

